Risk Evaluation of the Spring Snowmelt Flood in Ili River Basin and It’s Mapping

This paper evaluates the risk of the spring snowmelt fl ooding, which is often occured in the Ili River Basin, based on GIS technology, information quantity model and impact factors including elevation, topographic relief degree, slope, distance from the river system, land use/cover types and winter snow depth. According to the fi nal comprehensive information quantity, the spring snowmelt fl ooding hazard may be divided into fi ve grades: very high, high, moderate, low and very low. Results show that the spring snowmelt fl oods concentrated mainly along the zonal river valley in the Ili River Basin, and are consistent with the distribution of winter snow-belt and farmland. The site number of spring snowmelt fl ooding hazards is positively correlated with the hazard grades. It is shown that the method based on the information quantity, and the mapping of spring snowmelt fl ood hazard zones is objective and has a better business value. The study may provide a technical support for a fi ne forecast of the spring snowmelt fl ood, and a valid basis to prevent from the spring snowmelt flood.